Secondary alkyl sulphates as wash



UNITED STATES PATENT oFFici:

SECONDARY ALKYL SULPHATES AS WASH- ING AND EMULSIFYING AGENTS Jacob N. Wickert, Charleston, W. Va., assignor, by

mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York No Drawing. Application January 10, 1935, Serial No. 1,172

8 Claims.

This invention relates to washing and emulsi-- tying operations; and more especially it concerns the utilization therein of water-soluble inorganic salts, and amine or substituted amine salts, of the half esters of sulphuric acid with saturated secondary branched-chain alcohols having at least 8 carbon atoms in the molecule. The invention is of special utility in the preparation and use of liquors employed in the treat- I 10 ment of textiles and fibrous substances, such as in wool scouring, and in the washing of cotton, wool, and silk textiles.

Heretoiore, there have been employed as detergents certain half sulphuric esters of primary l5 alcohols'or amines containing straight chains of 10 to 20 and more carbon atoms, and derived from the soap-forming fatty acids.

The present invention is based in important part uponthe discovery that salts of monoesters of sulphuric acid derived from saturated secondary branched-chain alcohols having 8 or more carbon atoms inthe molecule are highly eflicient cleansing agents and emulsificants, either when used alone, or with other detergents such as soap and sodium carbonate, in solutions in water or the usual volatile solvents.

The alkali metal salts and substituted amine salts of the half esters of sulphuric acid with secondary branched-chain aliphatic alcohols having 8 or more carbon atoms in the molecule possess in common strong detergent and emulsifying properties well adapting them for use in the preparation of cleaning, scouring, and emulsifying compositions. However, those derived, in the manner hereinafter indicated, from secondary aliphatic alcohols having 14 or more carbon atoms in the molecule are especially efiective in cleaning and washing operations conducted under neutral or alkaline conditions, reducing greatly the interiacial tension between the washing fluid and any oily or other materials presen in the material to be cleaned.

These sulphate esters of the higher secondary aliphatic alcohols exist as colorless, amorphous waxes, completely soluble in organic solvents such as alcohols, esters, ketones, and hydrocarbons; and they are much more soluble in water than are sulphuric acid esters of corresponding carbon content, derived from primary alcohols or those having straight carbon chains.

Those sulphate esters of the invention having less than 15 carbon atoms in the molecule are completely soluble in water, yielding a clear solution at 0.25% concentration at room temperature. Those having 15 or more carbon atoms in the molecule form faintly cloudy solutions which do not settle out upon standing; whereas soaps and other detergent solutions under similar conditions of concentration are very cloudy, and in many instances precipitate a solid after several days.

These new sulphate esters yield voluminous foams when shaken with warm water. The calcium and magnesium salts present in moderately hard waters are not precipitated by these compounds in dilute solutions, since their calcium and magnesium salts are almost as soluble as the sodium salts. Dilute aqueous solutions of the alkali metal sulphate esters when slightly acidified still retain a large proportion of their detergent properties. Such solutions evidently contain some alkyl hydrogen sulphate.

The neutral secondary alkyl sulphates of the present invention may be produced by condensing an aliphatic primary or secondary aldehyde having at least 4 carbon atoms in its molecule, with acetone, methylethyl ketone, or a ketone derivative of either, in the presence of an alkaline catalyst. By the term secondary aldehyde is meant an aldehyde in which the carbon atom connected with the aldehyde group is also directly connected with 2, and only 2, other carbon atoms.

The resultant reaction mixture is made slightly acid to phenolphthalein by means of a suitable acid, and the acidified mixture is heated to its boiling point, thus converting the ketol present as a result of the condensation of the aldehyde and ketone, into an unsaturated ketone. The mixture is fractionally distilled under vacuum to separate the unreacted starting materials and water from the ketone; and to isolate the ketone from the said mixture. This ketone is hydrogenated under superatmospheric pressure, preferably around 800-1000 pounds per square inch, and at temperatures up to around C., in the presence of a hydrogenation catalyst such as active nickel. The saturated secondary alcohol thus formed is then recovered by fractional distillation of the reaction mixture under vacuum, and is converted to its acid sulphate by any of the usual sulphating methods. According to one method, the secondary alcohol is reacted with approximately an equivalent amount of equimolar proportions of 96% sulphuric acid and acetic anhydride, at low temperatures maintained preferably from around 0 to around 10 C. The concentration of the sulphuric acid can vary considerably: or this acid or sulphuric anhydride can be used alone;

and other anhydrides of organic acids, or the acids themselves, or their chlorides, may be substituted for the acetic anhydride; or chlorsulphonic acid dissolved in a suitable diluent such 1 as detergents in the washing of textiles and other materials soiled with grease, paint, carbon, and other objectionable substances, are those listed in Table I.

Table I t; Apparent formula of inter- Substance mediate alcohol ga atoms 1. Sodium octylsulufhato.-- 3, methylheptanol-2 s 2. Sodiumnonyls phate..- 3,ethylheptanol-6 9 3. Sodium docylsufphata--- 2methylnonanol-4. 10 4. Sodiumundecylsulphato. 5ethyln0nan0l-2 11 5. Sodiumdodecylsulphate, 3,ethyl-8-methylnona l2 6. Sodiumtridecylmlphate- 3,ethylundecanol-6 l3 7. Sodignze tetradecyl sul- 7,ethyl-2-methylundecanol- 14 8 8. sm l m pantadecyl sul- 3,9 diethylundecanol-o.- 15

p e 9. Scul pentadecyl sul-' 5,ethy ltrldecanol-8 15 p l0. Sodiglrn hexadecyl sul- 9, ethyl-o-methyltridecanol- 16 D 11. Sodiggi haptadecyl 8111- 3,9 diethyltridecanol-G. 17 '12. Sotfign; nondecyl sul- 5,11 diethylpentadecanolt..- 19

p a o 13. 'MJtfiAt. tetradecyl sul- 7,ethyl-2rnethy1undecanol- 16 p a e 14. 'M.E Aieheptadecyl sul- 3,9 diethyltridecanol-fi. 19

a 15. nondecyl sul- 5,11 diethylpentadecanol-8 21 p e 16."T.E.A. tetradecyl sul- 7, 2thyl-2-methylundecanol- D 9 l7."'-T.E.A. heptadecyl sul- 3,9 diethyltridecanol-fl 23 p 18. "T.E.A. nondecyl-sulphate- 5,11 diethylpentadecanol-S.-. 25

Table II 0.25% aqueous solution Intel-facial Numbers cones. to substance] Drop mum tension bar at dynes per 0. cm. at 26 Water 22 43. 3

atom of the main chain spaced from that carbon atom to which the sulphate group is attached; and that many of the alkyl sulphates have two branched-chain alkyl groups respectively connected directly to the carbon atom to which the sulphate group is attached. These structural characteristics possessed by so many compounds of this class examined appear to have an important bearing on the emciency of such compounds as detergents and emulsifying agents in the compositions employed.

The power of depressing the interfacial tension between water and hydrocarbons is one of the properties possessed to a remarkable degree by the sulphate esters of secondary branchedchain alcohols of the invention. Evaluation of this power may beobtained by drop number measurements. Those recorded in Table I consist in counting the number of drops formed by a plane-ground capillary tip when a fixed volume (10 c. c.) of an aqueous solution containing 25% by weight of the sample is allowed to flow slowly into a body of kerosene maintained at 30 C. The tip is of such size that the fixed volume of water, selected as a standard, will be divided into about 25 drops. The rate of flow is so regulated that the drops will form distinctly and can be counted conveniently. The number of drops observed may vary somewhat from one sample to another, particularly when the number is in excess of 100. Therefore, the values here recorded are in some cases the average of those found for several samples. This depressing power is measured directly by the number of drops formed. It is closely related to the detergent power, and particularly to the emulsifying power, of the sample.

Reference to the table will show the greatly increased effectiveness of the neutral alkyl sulphates having 14 or more carbon atoms in their molecules over those of lower molecular weight for depressing the interfacial tension between aqueous solutions and hydrocarbons.

The following examples will serve to illustrate the invention:

Example 1 A soiled white silk cloth impregnated with carbon black, mineral oil, manganese dioxide, and carbon tetrachloride, was agitated for five minutes in a .25% aqueous solution of sodium nondecyl sulphate (see Table I) The cloth was then rinsed with water and dried. Practically all of the color imparted by the impurities was removed in the washing, and the white color of the cloth restored. Similarly, the monoand triethanolamine heptadecyl and nondecyl sulphates were highly effective detergents in washing silk.

Example 2 A soiled white cotton cloth stained with mineral oil, carbon black, and manganese compounds, was treated with an aqueous solution of sodium heptadecyl sulphate, following the procedure described in Example 1. After rinsing the washed cloth in water and drying it, the color imparted by the impregnating materials had been in main part eliminated.

Unboiled cotton yarn was soaked in a dilute aqueous solution of the sodium nondecyl sulphate, and when dried was very appreciably whiter and softer, indicating a strong cleaning action.

The higher members of the series of sulphate esters, those having 14 or more carbon atoms in the molecules, have a detergent power superior to the lower members of the series; although it has been discovered that blends of the compounds of higher carbon content than 14 carbon atoms with those of lower carbon content are eificient cleansers in certain instances, and have better hard water and sea water solubility than those of the higher carbon content alone. Blends of one or more of these sulphate esters with ordinary soaps also are good detergents.

Hands soiled with grease, fresh paint, and other forms of dirt readily are washed clean .with water containing any of the sulphate esters of the invention. A copious lather is obtained, and the soil is removed as completely and efliciently as with special pumice-base soaps and others.

'Ifieggtiles readily may be washed clean in aqueous or solvent solutions containing hardness-1m parting ingredients or acidic substances, by the employment of a small amount of the sulphate esters of one of the secondary alcohols produced in the manner herein described. voluminous suds or froth which are relatively stable are formed r upon shaking dilute solutions of these sulphate esters. For example, upon agitating a .25% aqueous solution of the sodium tetradecyl sulphate, or of the corresponding monoor triethanolamine salt thereof, in hard water containing 400 parts per million of CaClz, a voluminous foam is produced which has over 15 times the volume of the foam produced under similar conditions using a sulphation product now on the market for the purpose and made from technical oleyl alco-' hols. Moreover, whereas the foam produced by the said sulphate esters of the present invention persisted for over two hours after agitation had ceased, the foam produced by the oleyl alcohol derivatives lasted but six seconds.

When sea water .was substituted for the hard water mentioned above, the tetradecyl sulphates of this invention gave foams which persisted for over two hours, whereas the oleyl alcohol derivatives produced but from one-third to one-half as much foam, which vanished in eight seconds after discontinuing the agitation.

The invention -is susceptible of modification within the scope of the appended claims:

I claim:

1. In the process of washing textiles, the step which comprises agitating the same while immersed in a solution of a neutral water-soluble salt of a sulphuric acid ester derived from a saturated secondary branched-chain monohydric aliphatic alcohol, and having at least 14 carbon atoms in its molecular structure.

2. The process forcleaning textile materials,

which comprises contacting the said materials with an aqueous solution having therein a watersoluble salt of an acid sulphuric ester of a saturated secondary branched-chain monohydric aliphatic alcohol having at least 14 carbon atoms in its molecular structure.

3. A detergent and emulsifying composition, which comprises a solution of a water-soluble sulphuric acid ester of a saturated secondary branched-chain -monohydric aliphatic alcohol containing at least 8 carbon atoms in its molecule and having two branched-chain alkyl groups respectively connected directly to the carbon atom to which the sulphuric acid group is attached.

4. A detergent and emulsifying composition, which comprises a solution of' a water-soluble salt of a sulphuric acid ester of a secondary branched-chain monohydric aliphatic alcohol containing at least 14 carbon atoms in its molecule.

5. A detergent and emulsifying composition, which comprises a solution of a water-soluble salt of a sulphuric acid ester of a secondary branchedchain monohydric aliphatic alcohol containing from 14 to 19 carbon atoms in its molecule.

6. A detergent composition comprising a solution of a water soluble sulphate ester of a saturated secondary branched-chain monohydric alcohol, which ester has at least 8 carbon atoms in its molecule and has at least one alkyl sidechain directly connected with the third carbon atom of the main chain spaced from that carbon atom to which the sulphate group is attached.

7. In the process of washing textiles, the step which comprises contacting the same with a solution of a water-soluble sulphate ester of a satu: rated secondary branched-chain monohydric aliphatic alcohol having at least 8 carbon atoms in its molecule and having two branched-chain alkyl groups respectively connected directly to the carbon atom to which the sulphate group is attached.

8. In the process of washing textiles, the step which comprises contacting the said materials with a solution of a water-soluble sulphate ester of a saturated secondary branched-chain monohydric aliphatic alcohol having at least 8 carbon atoms in its molecule and having at least one alkyl side-chain directly connected with the third carbon atom of the main chain spaced from that carbon atom to which the sulphate group is attached.

JACOB N. WICKERT.

CERTIFICATE OF CORRECTION.

' Patent No. 2,088,020.

July 27, 1937.

JACOB N. WICKERT.

It is hereby-certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 49, inthe table, strike out "Table II"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case. in the Patent Office.

Signed and sealed this 21st day of September,A. D. 1937.

Henry Van Arsdale 

